#define _CRT_SECURE_NO_WARNINGS 1

#include<iostream>
#include<vector>
#include<unordered_map>
using namespace std;
class Solution {
public:
    int mySqrt(int x)
    {
        if (x < 1)return 0;
        int left = 1;
        int right = x;
        while (left < right)
        {
            long long mid = left + (right - left + 1) / 2;
            long long target = mid * mid;
            if (target <= x)
            {
                left = mid;
            }
            else
            {
                right = mid - 1;
            }
        }
        return left;
    }
};
int main()
{
    Solution y;
        cout << y.mySqrt(1024) << endl;
    return 0;
}
